DE112012004506B4 - Belt tensioner for a safety belt system - Google Patents

Abstract

Belt tensioner for a safety belt system, with a belt shaft housing (18) which is U-shaped in axial section and has a housing web (24) and two opposite housing legs (26, 28), each housing leg (26, 28) having a housing opening (30, 32); end (14) of a belt strap (16), the belt shaft (12) having a recess (22) for receiving the belt shaft insertion element (20), and the belt shaft insertion element (20) being insertable radially into the recess (22). characterized in that the distance (77) between the housing legs (26, 28) in the area of the housing web (24) is greater than the distance (78) of the housing legs (26, 28) in the area of the free leg ends (79).

Description

The invention relates to a belt tensioner for seat belt systems in motor vehicles, in particular an end fitting tensioner.

Belt tensioners for seat belt systems are already generally known from motor vehicle technology. In the case of so-called end fitting tensioners, when the belt tensioner is activated, the actually fixed end of a belt strap, which is usually connected to the seat frame or the vehicle body, is tightened in order to tighten the entire belt strap. Both linearly operating and rotary end fitting tighteners are described in the prior art. In the case of rotary end fitting tensioners, the end of the belt webbing is connected to a belt shaft, which is driven when the belt tensioner is activated in order to wind the belt webbing onto the belt shaft.

For the assembly of the seat belt system, especially with regard to end fitting tensioners, a process is increasingly desired in which the end of the belt webbing is attached to the belt tensioner only after the belt tensioner has been assembled on the vehicle body or on the seat frame.

To enable such a subsequent attachment of the webbing, proposes DE 103 13 551 B3 propose a seat belt retractor in which a hollow belt shaft rotatably mounted in the belt shaft housing has an opening at the front and an axially aligned belt shaft slot. In addition, a through-slot is provided in a housing leg of the belt shaft housing, so that the end of the belt strap designed as an end loop can be inserted in the axial direction into the hollow belt shaft and fixed there together with a belt pin inserted in the end loop.

However, this subsequent attachment of the belt strap to the belt shaft requires considerable installation space in the axial direction, which is not always available in the area of an end fitting tightener that has already been installed. Thus, in the case of cramped installation space, the proposed fastening of the end of the belt webbing to the belt shaft is not possible or only possible with a great deal of assembly effort.

From the post-published generic DE 10 2011 051 795 A1 a belt tensioner for a seat belt system is known, which has a belt shaft housing that is essentially U-shaped in axial section, with a housing web and two opposite housing legs, each housing leg having a housing opening through which a belt shaft extends, which in the belt shaft housing an axis is rotatably mounted. The seat belt tensioner also has a belt shaft insertion element, to which one end of a belt strap is attached, the belt shaft having a recess for receiving the belt shaft insertion element, and the belt shaft insertion element being radially insertable into the recess.

From the DE 28 02 031 A1 it is known to fasten the webbing to the belt shaft by means of a radially insertable belt pin.

The object of the invention is to create a belt tensioner in which the end of a belt strap can be subsequently attached to a belt shaft of the rotary belt tensioner with little assembly effort and in which the belt forces that occur can be absorbed without any problems.

In the belt tensioner of the generic type, no axial assembly space is required in order to attach the end of the belt to the belt shaft. The radial installation space that is required instead is available anyway, since the belt webbing extends radially away from the belt shaft through precisely this space used for fastening the belt webbing in the fully assembled state of the safety belt system.

According to the invention, the distance between the housing legs in the area of the housing web is greater than in the area of the free ends of the legs. This results in a kind of "omega shape" of the belt shaft housing, which means that the belt forces that occur can be absorbed without any problems. In addition, an advantageous bearing for the spool is provided, so that the spool can be produced as a cast part, in particular made of die-cast zinc.

In one embodiment of the belt tensioner, the belt shaft has a fork bearing for non-rotatably fixing the belt shaft insertion element, with the belt shaft insertion element being able to be inserted essentially radially into the fork bearing. This fork bearing enables a non-rotatable connection between the belt shaft insertion element and the belt shaft with little effort. For this purpose, the belt shaft insertion element is designed, for example, as a thick plate or rod with a substantially rectangular or trapezoidal cross section and is accommodated with a precise fit in the fork bearing.

Opposite axial ends of the spool shaft insertion element preferably extend axially beyond the belt webbing, the axial ends being designed as bearing sections for mounting the spool shaft insertion element in the spool shaft. This ensures in a simple way that the bearing sections of Gurtwel len slide-in elements do not impede the winding up of webbing during the tightening process.

Furthermore, the belt shaft insertion element can be designed symmetrically, in particular as a symmetrical steel plate. This symmetry simplifies subsequent attachment of the webbing to the spool and prevents assembly errors.

In the case of the belt tensioner according to the invention, the end of the belt webbing is preferably sewn into a loop, with the loop enclosing at least part of the belt shaft insertion element. Forming a loop is a simple, inexpensive and reliable way of attaching a webbing end.

In a further embodiment of the belt tensioner, the belt shaft has shaft stubs at its axial ends, which are connected by a belt shaft web. In this way, in the area of the spool web, the spool insertion element with the attached webbing can be accommodated without any problems, while the stub shafts allow the spool to be mounted in the spool housing in a simple manner so that it can rotate about an axis.

In this embodiment of the belt tensioner, a fork bearing for the belt shaft insertion element is preferably formed in at least one shaft stub. For example, the fork bearing is designed as a radial bearing slot in the stub shaft, in which a bearing section of the spool insert element engages in a form-fitting manner in order to connect the spool shaft insert element to the spool in a rotationally fixed manner.

Preferably, the spool and particularly preferably also the spool housing are symmetrical. Similar to the symmetrical design of the belt shaft insertion element, this symmetry also contributes to reducing assembly errors and thus to easier assembly. In addition, due to the symmetrical individual components, both a belt tensioner for the driver's side and (inverted) a belt tensioner for the passenger's side of a motor vehicle can be assembled with identical components. This reduces the variety of components and the associated storage costs and further simplifies the assembly of the seat belt system.

In a further embodiment of the belt tensioner, the belt shaft housing is U-shaped in an axial section and has a housing web and two opposite housing legs, each housing leg having a housing opening through which the belt shaft extends. Such a spool housing can be produced with little effort as a bent stamped part made of sheet metal, in particular sheet steel.

The distance between the housing legs preferably changes in the area of the housing openings, particularly preferably only in the area of the housing openings.

• - 1 einen axialen Längsschnitt durch einen erfindungsgemäßen Gurtstraffer;
• - 2 eine Draufsicht des Gurtstraffers gemäß 1;
• - 3 eine Seitenansicht des Gurtstraffers gemäß 1;
• - 4 eine weitere Seitenansicht des Gurtstraffers gemäß 1;
• - 5 eine Draufsicht eines Gurtwellen-Einschubelements für den Gurtstraffer gemäß den 1 bis 4;
• - 6 eine Draufsicht und eine Seitenansicht des an einem Gurtband befestigten Gurtwellen-Einschubelements gemäß 5;
• - 7 eine perspektivische Ansicht des am Gurtband befestigten Gurtwellen-Einschubelements gemäß 6 vor der Montage an einer Gurtwelle;
• - 8 eine perspektivische Ansicht der in einem Gurtwellengehäuse gelagerten Gurtwelle mit montiertem Gurtband;
• - 9 eine perspektivische Ansicht des Gurtstraffers gemäß den 1 bis 4 vor der Montage des Gurtwellen-Einschubelements;
• - 10 eine perspektivische Ansicht des Gurtstraffers gemäß den 1 bis 4 bei der Montage des Gurtwellen-Einschubelements;
• - 11 eine perspektivische Ansicht des Gurtstraffers gemäß den 1 bis 4 nach der Montage des Gurtwellen-Einschubelements und vor der Montage einer Gurtwellen-Sicherungseinheit;
• - 12 eine perspektivische Ansicht des Gurtstraffers gemäß den 1 bis 4 im fertig montierten Zustand;
• - 13 eine Detailansicht eines Gurtwellengehäuses für den Gurtstraffer gemäß den 1 bis 4;
• - 14 eine perspektivische Ansicht des Gurtwellengehäuses gemäß 13;
• - 15 eine Seitenansicht des Gurtwellengehäuses gemäß 13;
• - 16 das Gurtwellen-Einschubelement für den erfindungsgemäßen Gurtstraffer gemäß einer alternativen Ausführungsform;
• - 17 das Gurtwellen-Einschubelement für den erfindungsgemäßen Gurtstraffer gemäß einer weiteren alternativen Ausführungsform;
• - 18 einen Schnitt durch das Gurtwellen-Einschubelement für den erfindungsgemäßen Gurtstraffer gemäß einer weiteren alternativen Ausführungsform;
• - 19 eine perspektivische Ansicht des Gurtwellen-Einschubelements gemäß 18;
• - 20 das Gurtwellen-Einschubelement für den erfindungsgemäßen Gurtstraffer gemäß einer weiteren alternativen Ausführungsform beim Zusammenbau;
• - 21 das Gurtwellen-Einschubelement gemäß 20 nach seinem Zusammenbau;
• - 22 das Gurtwellen-Einschubelement gemäß 21 im Schnitt; und
• - 23 eine schematische Perspektivansicht eines erfindungsgemäßen Gurtstraffers mit alternativem Strafferantrieb.

Further features and advantages of the invention result from the following description of preferred embodiments with reference to the drawings. In these show:

• - 1 an axial longitudinal section through a belt tensioner according to the invention;
• - 2 a top view of the belt tensioner according to FIG 1 ;
• - 3 according to a side view of the belt tensioner 1 ;
• - 4 according to another side view of the belt tensioner 1 ;
• - 5 a top view of a belt shaft insertion element for the belt tensioner according to FIG 1 until 4 ;
• - 6 a plan view and a side view of the belt shaft insertion element attached to a webbing according to FIG 5 ;
• - 7 a perspective view of the belt shaft insertion element attached to the belt according to FIG 6 before mounting on a spool;
• - 8th a perspective view of the belt shaft mounted in a belt shaft housing with the belt strap installed;
• - 9 a perspective view of the belt tensioner according to the 1 until 4 before installing the spool shaft slide-in element;
• - 10 a perspective view of the belt tensioner according to the 1 until 4 when assembling the spool shaft insertion element;
• - 11 a perspective view of the belt tensioner according to the 1 until 4 after the assembly of the belt shaft insertion element and before the assembly of a belt shaft securing unit;
• - 12 a perspective view of the belt tensioner according to the 1 until 4 in fully assembled condition;
• - 13 a detailed view of a Gurtwellengehäuse for the belt tensioner according to 1 until 4 ;
• - 14 a perspective view of Gurtwellengehäuse according to 13 ;
• - 15 a side view of the spool housing according to FIG 13 ;
• - 16 the belt shaft insertion element for the belt tensioner according to an alternative embodiment;
• - 17 the belt shaft insertion element for the belt tensioner according to a further alternative embodiment;
• - 18 a section through the Gurtwellen insertion element for the belt tensioner according to the invention according to a further alternative embodiment;
• - 19 a perspective view of Gurtwellen insertion element according to 18 ;
• - 20 the belt shaft insertion element for the belt tensioner according to the invention according to a further alternative embodiment during assembly;
• - 21 according to the belt shaft insertion element 20 after its assembly;
• - 22 according to the belt shaft insertion element 21 on average; and
• - 23 a schematic perspective view of a belt tensioner according to the invention with an alternative tensioner drive.

the 1 until 4 show a belt tensioner 10 for a seat belt system in a motor vehicle, specifically a so-called end fitting tensioner, with a belt shaft 12 to which one end 14 of a belt strap 16 is fixed, and a belt shaft housing 18 that can be fixed to the body and in which the belt shaft 12 is mounted, the belt shaft 12 can be rotated relative to the belt shaft housing 18 after activation of the belt tensioner 10 in order to wind up belt webbing 16 .

In the exemplary embodiment shown, the end 14 of the belt strap 16 is sewn into a loop which encloses a belt shaft insertion element 20, the belt shaft insertion element 20 being received in a recess 22 in the belt shaft 12 and being mounted in a rotationally fixed manner relative to the belt shaft 12.

According to 2 The belt shaft housing 18 of the belt tensioner 10 is U-shaped and comprises a housing web 24 and two opposite housing legs 26, 28, each housing leg 26, 28 having a housing opening 30, 32 through which the belt shaft 12 extends. Also provided is a fastening lug 33 which is bent off the housing web 24 and by means of which the belt shaft housing 18 can be firmly connected, in particular screwed, to a vehicle seat or a vehicle body.

The spool 12 is rotatably mounted about an axis A in the spool housing 18 . A cover cap 34 or a cable spool 36 is arranged on the axial ends of the spool 12, with the cover cap 34 and the cable spool 36 being firmly connected to the spool 12, in particular being pressed, and preventing or inhibiting an axial movement of the spool 12 relative to the spool housing 18 minimize a small axial play.

In order to be able to tighten the belt webbing 16 when the belt tensioner 10 is activated, a force transmission element 38 is provided, which couples the belt shaft 12 to a tensioner drive 40 . In the exemplary embodiment shown, the force transmission element 38 is a traction cable 41 which is partially wound onto the cable reel 36 and is attached to the cable reel 36 with one end of the cable.

The tensioner drive 40 of the belt tensioner 10 comprises a tensioner tube 42 for accommodating and guiding a pressure application element 44 and a separate generator housing 46 for accommodating a gas generator 48. In the exemplary embodiment shown, the generator housing 46 is a piece of pipe, so that both the tensioner tube 42 and the generator housing 46 consist of one Metal tube, in particular a steel tube are made. In addition, a coupling element 50 is provided, which firmly connects the generator housing 46 to the pretensioner tube 42 (cf. 1 ).

The pressurizing element 44 is according to 1 a piston substantially sealed within arcuate pretensioner tube 42 and slidably received along a tube axis. The traction cable 41, which is attached to the cable reel 36 with one end of the cable, extends from the cable reel 36 into the tensioner tube 42 and is attached there to the piston with an opposite cable end. After activation of the gas generator 48, the piston is subjected to gas pressure and moves in the direction of a free tube end 52 of the tensioner tube 42. As the spool 12 rotates, the traction cable 41 is unwound from the cable spool 36 and at the same time the belt 16 is wound onto the spool 12 , so that a belt tightening takes place.

In order to strengthen the connection between the tensioner tube 42 and the generator housing 46 and to create a simple connection between the tensioner drive 40 and the belt shaft housing 18, a stabilization unit 54 is also provided. In the present case, this stabilization unit 54 comprises two stabilization elements 55, in particular made of die-cast zinc, and a For example, connecting element 56 designed as a tubular rivet (cf. 3 and 4 ).

Of course, the belt tensioner 10 according to the 1 until 4 can also be driven by a hydraulic motor or be equipped with another alternative tensioner drive 40, in particular a so-called "power snake" drive. In 23 a combination drive 57 with a "power snake" 58 as a pressure application element 44 and a traction cable 41 is shown as an example. The power snake 58 is a flexible, elastically and/or plastically deformable plastic element, which is accommodated in the tightening tube 42 in a largely sealed manner and is guided in a longitudinally displaceable manner. After belt tensioner 10 has been activated, gas pressure is applied to power snake 58 and it is displaced in the direction of free tube end 52, power snake 58 being deformed by a drive pinion 59 in such a way that it engages in drive pinion 59 and drives it in the tightening direction. In this case, the traction cable 41 is wound onto a cable drum 60 of the drive pinion 59 and, on the other hand, is unwound from the cable reel 36 of the belt tensioner 10 while the belt shaft 12 rotates, so that the belt is tensioned.

In the illustrated embodiments, the belt tensioner 10 has a particularly advantageous construction, which below with reference to the 5 until 15 is explained in more detail.

the 5 shows the belt shaft insertion element 20, which is a stamped and optionally formed metal plate here by way of example. Otherwise, the belt shaft insertion element 20 is designed symmetrically, in particular as a symmetrical steel plate.

According to 6 the end 14 of the webbing 16 is sewn into a loop, the loop enclosing the belt shaft insertion element 20 . Thus, the end 14 of the webbing 16 is reliably attached to the spool insertion member 20 .

Opposite axial ends of the spool insertion element 20 extend axially beyond the webbing 16 , the axial ends being designed as bearing sections 61 for mounting the spool insertion element 20 in the spool 12 .

the 7 shows a perspective view of the belt shaft 12 with the recess 22 for receiving the belt shaft insertion element 20, wherein the belt shaft insertion element 20 can be inserted essentially radially with respect to the axis A into the recess 22.

In the present exemplary embodiment, the belt shaft 12 has a fork bearing 62 for the non-rotatable fixing of the belt shaft insertion element 20 , with the belt shaft insertion element 20 being able to be inserted essentially radially into the fork bearing 62 .

The spool 12 has shaft stubs 64, 66 at its axial ends, which are connected by a spool web 68 (cf. 9 ) are connected. As a result of this construction, the recess 22 for receiving the spool insertion element 20 is created in the area of the spool web 68 and in the area of the shaft stubs 64, 66 a mounting of the spool 12 in the spool housing 18 that is rotatable about the axis A ( 8th ).

Out 7 combined with 1 also shows that in both stub shafts 64, 66 a fork bearing 62 for the belt shaft insertion element 20 is formed. In the present case, these fork bearings 62 are radial bearing slots 70, into which the bearing sections 61 of the belt shaft insertion element 20 fit precisely and form-fittingly, so that the belt shaft insertion element 20 in the assembled end state according to FIG 8th is rotatably connected to the spool 12.

the 9 until 12 show the sequence of a subsequent assembly of the webbing 16 on the belt tensioner 10, which has already been installed in advance on a seat frame or a body of the motor vehicle.

According to 9 the belt shaft insertion element 20 with the belt strap 16 attached to it is fed to the already installed part of the belt tensioner 10 until the bearing sections 61 of the belt shaft insertion element 20 are located radially outside of the fork bearings 62 formed in the belt shaft 12 (cf. 10 ).

As in 10 indicated by an arrow 72, the spool shaft insertion element 20 can then be inserted into the recess 22 and the fork bearing 62 by means of a radial movement relative to the spool shaft 12, so that the spool shaft insertion element 20 is connected to the spool shaft 12 in a rotationally fixed manner (cf. 11 ).

According to FIG 11 a spool securing unit 74 is pushed between the spool 12 and the housing web 24 of the spool housing 18 and fixed to the spool housing 18 ( 12 ). This belt shaft securing unit 74 is designed in such a way that it only engages when the belt shaft insertion element 20 is correctly installed on the belt shaft 12 can be pushed, so that incorrect assembly of the belt shaft insertion element 20 on the belt shaft 12 is ruled out.

In addition, the belt shaft securing unit 74 has spring elements 76 which, in the fully assembled state of the belt tensioner 10 according to FIG 12 apply the spool 12 in its locked position.

the 13 until 15 show different detailed views of the spool housing 18. It is clear that the spool housing 18 is U-shaped in an axial section and has the housing web 24 and two opposing housing legs 26, 28, with each housing leg 26, 28 having a housing opening 30, 32 which the belt shaft 12 can extend (cf. 1 and 2 ).

A distance 77 between the housing legs 26, 28 in the area of the housing web 24 is greater than a distance 78 in the area of the free leg ends 79, so that the housing shape in this axial section is reminiscent of the Greek capital letter “Omega”.

The distance between the housing legs 26, 28 changes according to the 13 and 14 exclusively in the area of the housing openings 30, 32.

This housing shape contributes to a particularly advantageous flow of forces within the belt tensioner 10 . This housing shape makes it possible to hang the spool insertion element 20 sewn into the spool 16 in order to introduce the load into the spool 12 and to dimension it so that the breaking load is introduced into the spool housing 18 via the spool insertion element 20 . This makes it possible to manufacture the spool 12 as a cast part, in particular from die-cast zinc.

the 16 shows the belt shaft insertion element 20 with attached belt strap 16 according to an alternative embodiment. In this case, the belt shaft insertion element 20 is designed in two parts, with a base body 80 to which the end 14 of the belt strap 16 is attached, and a winding body 82 which is connected to the base body 80 in a rotationally fixed manner. The bobbin 82 serves to provide a more symmetrical, ideally circular, core for winding the webbing 16 .

The base body 80 and the winding body 82 can, under certain circumstances, be screwed together, which is achieved by means of a threaded bore 84 in 16 is indicated. In this case it is conceivable also to screw the spool 12, specifically the spool web 68 of the spool 12, to the spool insertion element 20, specifically the base body 80 and the winding body 82. Correct assembly of the belt shaft insertion element 20 on the belt shaft 12 can also be ensured via this screw connection, if necessary with a torque query, so that the belt shaft securing unit 74 can be dispensed with with regard to this function.

the 17 shows a further alternative embodiment of a two-part belt shaft insertion element 20, which differs from the embodiment according to FIG 16 differs only by the connection between the base body 80 and the winding body 82.

the 18 and 19 12 show another alternative embodiment of a two-piece belt shaft insertion element 20, which in turn differs only in the shape of the base body 80 and the winding body 82 compared to the two previous embodiments.

The aim of these multi-part spool slide-in elements 20 is, together with the spool web 68 of the spool 12 (cf. 9 ) to provide a core that is as symmetrical as possible, ideally circular, with respect to the axis A, for winding up the webbing 16 .

the 18 until 20 show a further alternative embodiment of a belt shaft insertion element 20 constructed in several parts, which already comes very close to an ideal, circular core for winding up the belt webbing 16 .

The base body 80, designed as an insertion pin, of the belt shaft insertion element 20 according to FIG 18 first inserted into the loop formed at the end 14 of the webbing 16 and fixed radially by two intermediate elements 86 . The two-part winding body 82 is then arranged and the multi-part belt shaft insertion element 20 is fixed by a screw screwed into the threaded bores 84 .

Claims (10)

Belt tensioner for a safety belt system, with a belt shaft housing (18) which is U-shaped in an axial section and has a housing web (24) and two opposite housing legs (26, 28), each housing leg (26, 28) having a housing opening (30 , 32), a spool (12) which is rotatably mounted in the spool housing (18) about an axis (A) and extends through the housing openings (30, 32), and a spool shaft insertion element (20). to which one end (14) of a belt strap (16) is fastened, the belt shaft (12) having a recess (22) for receiving the belt shaft insertion element (20), and the belt shaft insertion element (20) being inserted radially into the recess ( 22) can be inserted, characterized in that the distance (77) between the housing legs (26, 28) in the area of the housing web (24) is greater than the distance (78) between the housing legs (26, 28) in the area of the free leg ends ( 79). belt tensioner after claim 1 , characterized in that the belt shaft (12) has a fork bearing (62) for non-rotatably fixing the belt shaft insertion element (20), the belt shaft insertion element (20) being radially insertable into the fork bearing (62). belt tensioner after claim 1 or 2 , characterized in that opposite axial ends of the belt shaft insertion element (20) extend axially beyond the belt webbing (16), the axial ends serving as bearing sections (61) for mounting the belt shaft insertion element (20) in the belt shaft (12) are trained. Belt tensioner according to one of the preceding claims, characterized in that the belt shaft insertion element (20) is designed as a symmetrical steel plate. Belt tensioner according to one of the preceding claims, characterized in that the end (14) of the belt strap (16) is sewn into a loop, the loop enclosing at least part of the belt shaft insertion element (20). Belt tensioner according to one of the preceding claims, characterized in that the belt shaft (12) has shaft stubs (64, 66) at its axial ends, which are connected by a belt shaft web (68). belt tensioner after claim 6 , characterized in that in at least one stub shaft (64, 66) a fork bearing (62) for the belt shaft insertion element (20) is formed. Belt tensioner according to one of the preceding claims, characterized in that the belt shaft (12) is symmetrical. Belt tensioner according to one of the preceding claims, characterized in that the belt shaft housing (18) is symmetrical. Belt tensioner according to one of the preceding claims, characterized in that the distance between the housing legs (26, 28) changes in the area of the housing openings (30, 32).

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